Speaking as a FORMER N2O user, the "wet" kits are cheaper and easier to install, and will give you the moderate performance boost that most people want. The "dry," multipoint setups are considerably more expensive, a lot harder to install properly, and are capable of SOOO much more power increase, that for an occasional user, it's just too far over the top. The "dry" kits from my experience, are essentially identical to the wet kits, except that instead of mounting a nozzle right in front of the T-body, there are individual nozzles mounted in EACH intake runner, for a total of 8... Assuming you have a stout enough fuel supply, a bottle warmer, and big enough lines, you could theoretically jet each of the nozzles for 150HP flow, and have a 1200HP shot, assuming that the motor will take it. Putting that on the ground is another matter, though...
On the mod motors, Steeda's delete plates are available with nitrous nozzle bungs drilled and tapped, and all the lines can be run under the intake manifold, with the solenoids mounted to the stock CMCV motor tab, for a nearly invisible setup. Plumbing it won't be that big of a hassle either, assuming you're handy with a tubing bender.
If you're looking for something sane, like a 75-150HP bump, then a single nozzle in the CAI tube is a lot easier, cheaper, and I guess "safer," since there's a lot less to go wrong. That said, I lifted the top half of a 351C with a 150HP setup, so it's still not foolproof. My issue was a hung N20 solenoid.